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Measurement of hot-electron-driven fast ions in polar-direct drive exploding pusher implosions at the NIF

ORAL

Abstract

When hot electrons, generated through laser-plasma interactions (LPI) such as two-plasmon decay (TPD) or stimulated raman scattering (SRS), are accelerated away from a directly driven inertial confinement fusion implosion, the resulting charge gap can lead to acceleration of ions on the capsule surface to MeV energies. In this talk, we will show the first measurements of such MeV protons from polar direct drive exploding pusher (PDXP) implosions on the NIF. Correcting for blowby due to the large NIF laser spots to calculate an effective intensity on capsule, the maximum proton energies generated through this mechanism at NIF are higher than previously observed at OMEGA, but lower than predicted from TPD common wave theory. We explore if this observation is consistent with SRS being the dominant hot-electron generating mechanism on NIF and TPD on OMEGA. In addition, strong energy modulations have been observed in broad spectra of ions born in the NIF PDXP implosions, and we discuss if this could also be related to LPI effects.

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Presenters

  • Maria Gatu-Johnson

    MIT Plasma Science and Fusion Center, MIT PSFC, MIT, Massachusetts Institute of Technology (MIT), Massachusetts Institute of Technology MI

Authors

  • Maria Gatu-Johnson

    MIT Plasma Science and Fusion Center, MIT PSFC, MIT, Massachusetts Institute of Technology (MIT), Massachusetts Institute of Technology MI

  • Patrick J Adrian

    Massachusetts Institute of Technology (MIT), Massachusetts Institute of Technology, Massachusetts Institute of Technology MIT, Massachusetts Institute of Technology MI

  • Johan A Frenje

    Massachusetts Institute of Technology MIT, MIT PSFC, Massachusetts Institute of Technology (MIT)

  • Tim M Johnson

    Massachusetts Institute of Technology, Massachusetts Institute of Technology MIT

  • Neel Kabadi

    Massachusetts Institute of Technology, MIT, Massachusetts Institute of Technology MIT, Massachusetts Institute of Technology (MIT)

  • B. G Lahmann

    Massachusetts Institute of Technology MIT, MIT

  • Richard Petrasso

    Massachusetts Institute of Technology MIT, MIT

  • Warren J Garbett

    AWE, AWE Plc, AWE plc

  • Stephen Craxton

    University of Rochester, LLE

  • Matthias Hohenberger

    Lawrence Livermore Natl Lab, LLNL

  • Heather D Whitley

    Lawrence Livermore National Lab, Lawrence Livermore Natl Lab

  • Charles B Yeamans

    Lawrence Livermore Natl Lab, LLNL, Lawrence Livermore National Lab, Lawrence Livermore Natl. Lab

  • Alex B Zylstra

    Lawrence Livermore Natl Lab, Lawrence Livermore National Laboratory